The visitors, in second last position on the league table, stunned Sundowns in the 11th minute when defender Mosa Lebusa scored from a corner-kick.
However, it was inevitable that the Cape Town side would battle to match the attacking flair of the Brazilians, as Sundowns are known.
The hosts equalised a minute later when the inspirational Percy Tau sent in a cross to the far post for Zimbabwean midfielder Khama Billiat to send into the Ajax goal-net.
Billiat was again in the thick of the action in the 27th minute, but this time was the centre of a hotly-disputed penalty awarded against Ajax goalkeeper Jody February for infringing on the Sundowns player. Ricardo Nascimento made no mistake from the spot-kick to put the log-leaders in front for the first time in the game.
With eight minutes to go to the break, Sundowns doubled their lead after some fine work between defender Motjeka Modisha and Sibusiso Vilakazi with the latter finishing off wide of goalkeeper February.
The victory took Sundowns to 59 points from 29 games and into an unassailable position, with just their final league fixture, away to Bloemfontein Celtic on May 12 still to be played. Next up for the local champions is a home leg CAF Champions League Group C fixture against Morocco’s Wyad Casablanca on May 5.
Ajax, on 31 points from 29 games, will have it all to do in their final league fixture of the season at home to Kaizer Chiefs, if they are to avoid the 15th spot and playoff action against National First Division sides to see who will play top flight football next season.